1、pom.xml要额外引入

org.springframework.cloud spring-cloud-context 2.0.3.RELEASE

2、bean上使用@RefreshScope注解

@Component
@ConfigurationProperties(prefix = “product”)
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@RefreshScope
public class Product {

private Long id;

private String productName;

private BigDecimal price;

}

3、利用RefreshScope搭配@ApolloConfigChangeListener监听实现bean的动态刷新，其代码实现如下

@ApolloConfigChangeListener(value=“product.properties”,interestedKeyPrefixes = {“product.”})
private void refresh(ConfigChangeEvent changeEvent){

refreshScope.refresh(“product”);

PrintChangeKeyUtils.printChange(changeEvent);
}

b、基于EnvironmentChangeEvent实现刷新

利用spring的事件驱动配合@ApolloConfigChangeListener监听实现bean的动态刷新，其代码如下

@Component
@Slf4j
public class UserPropertiesRefresh implements ApplicationContextAware {

private ApplicationContext applicationContext;

@ApolloConfigChangeListener(value=“user.properties”,interestedKeyPrefixes = {“user.”})
private void refresh(ConfigChangeEvent changeEvent){
applicationContext.publishEvent(new EnvironmentChangeEvent(changeEvent.changedKeys()));

PrintChangeKeyUtils.printChange(changeEvent);
}

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}

}

c、当bean上有@ConditionalOnProperty如何实现刷新

当bean上有@ConditionalOnProperty注解时，上述的两种方案可以说失效了，因为@ConditionalOnProperty是一个条件注解，当不满足条件注解时，bean是没法注册到spring容器中的。如果我们要实现此种情况的下的动态刷新，我们就得自己手动注册或者销毁bean了。其实现流程如下

1、当满足条件注解时，则手动创建bean，然后配合@ApolloConfigChangeListener监听该bean的属性变化。当该bean属性有变化时，手动把属性注入bean。同时刷新依赖该bean的其他bean

2、当不满足条件注解时，则手动从spring容器中移除bean，同时刷新依赖该bean的其他bean

其刷新核心代码如下

public class OrderPropertiesRefresh implements ApplicationContextAware {

private ApplicationContext applicationContext;

@ApolloConfig(value = “order.properties”)
private Config config;

@ApolloConfigChangeListener(value=“order.properties”,interestedKeyPrefixes = {“order.”},interestedKeys = {“model.isShowOrder”})
private void refresh(ConfigChangeEvent changeEvent){
for (String basePackage : listBasePackages()) {
Set conditionalClasses = ClassScannerUtils.scan(basePackage, ConditionalOnProperty.class);
if(!CollectionUtils.isEmpty(conditionalClasses)){
for (Class conditionalClass : conditionalClasses) {
ConditionalOnProperty conditionalOnProperty = (ConditionalOnProperty) conditionalClass.getAnnotation(ConditionalOnProperty.class);
String[] conditionalOnPropertyKeys = conditionalOnProperty.name();
String beanChangeCondition = this.getChangeKey(changeEvent,conditionalOnPropertyKeys);
String conditionalOnPropertyValue = conditionalOnProperty.havingValue();
boolean isChangeBean = this.changeBean(conditionalClass, beanChangeCondition, conditionalOnPropertyValue);
if(!isChangeBean){
// 更新相应的bean的属性值，主要是存在@ConfigurationProperties注解的bean
applicationContext.publishEvent(new EnvironmentChangeEvent(changeEvent.changedKeys()));
}
}
}
}

PrintChangeKeyUtils.printChange(changeEvent);
printAllBeans();
}

/**

• 根据条件对bean进行注册或者移除
• @param conditionalClass
• @param beanChangeCondition bean发生改变的条件
• @param conditionalOnPropertyValue
  */
  private boolean changeBean(Class conditionalClass, String beanChangeCondition, String conditionalOnPropertyValue) {
  boolean isNeedRegisterBeanIfKeyChange = this.isNeedRegisterBeanIfKeyChange(beanChangeCondition,conditionalOnPropertyValue);
  boolean isNeedRemoveBeanIfKeyChange = this.isNeedRemoveBeanIfKeyChange(beanChangeCondition,conditionalOnPropertyValue);
  String beanName = StringUtils.uncapitalize(conditionalClass.getSimpleName());
  if(isNeedRegisterBeanIfKeyChange){
  boolean isAlreadyRegisterBean = this.isExistBean(beanName);
  if(!isAlreadyRegisterBean){
  this.registerBean(beanName,conditionalClass);
  return true;
  }
  }else if(isNeedRemoveBeanIfKeyChange){
  this.unregisterBean(beanName);
  return true;
  }
  return false;
  }

/**

• bean注册
• @param beanName
• @param beanClass
  */
  public void registerBean(String beanName,Class beanClass) {
  log.info(“registerBean->beanName:{},beanClass:{}”,beanName,beanClass);
  BeanDefinitionBuilder beanDefinitionBurinilder = BeanDefinitionBuilder.genericBeanDefinition(beanClass);
  BeanDefinition beanDefinition = beanDefinitionBurinilder.getBeanDefinition();
  setBeanField(beanClass, beanDefinition);
  getBeanDefinitionRegistry().registerBeanDefinition(beanName,beanDefinition);

}

/**

• 设置bean字段值
• @param beanClass
• @param beanDefinition
  */
  private void setBeanField(Class beanClass, BeanDefinition beanDefinition) {
  ConfigurationProperties configurationProperties = (ConfigurationProperties) beanClass.getAnnotation(ConfigurationProperties.class);
  if(ObjectUtils.isNotEmpty(configurationProperties)){
  String prefix = configurationProperties.prefix();
  for (String propertyName : config.getPropertyNames()) {
  String fieldPrefix = prefix + “.”;
  if(propertyName.startsWith(fieldPrefix)){
  String fieldName = propertyName.substring(fieldPrefix.length());
  String fieldVal = config.getProperty(propertyName,null);
  log.info(“setBeanField–>fieldName:{},fieldVal:{}”,fieldName,fieldVal);
  beanDefinition.getPropertyValues().add(fieldName,fieldVal);
  }
  }
  }
  }

/**

• bean移除
• @param beanName
  */
  public void unregisterBean(String beanName){
  log.info(“unregisterBean->beanName:{}”,beanName);
  getBeanDefinitionRegistry().removeBeanDefinition(beanName);
  }

public T getBean(String name) {
return (T) applicationContext.getBean(name);
}

public T getBean(Class clz) {
return (T) applicationContext.getBean(clz);
}

public boolean isExistBean(String beanName){
return applicationContext.containsBean(beanName);
}

public boolean isExistBean(Class clz){
try {
Object bean = applicationContext.getBean(clz);
return true;
} catch (BeansException e) {
// log.error(e.getMessage(),e);
}
return false;
}

private boolean isNeedRegisterBeanIfKeyChange(String changeKey,String conditionalOnPropertyValue){
if(StringUtils.isEmpty(changeKey)){
return false;
}
String apolloConfigValue = config.getProperty(changeKey,null);
return conditionalOnPropertyValue.equals(apolloConfigValue);
}

private boolean isNeedRemoveBeanIfKeyChange(String changeKey,String conditionalOnPropertyValue){
if(!StringUtils.isEmpty(changeKey)){
String apolloConfigValue = config.getProperty(changeKey,null);
return !conditionalOnPropertyValue.equals(apolloConfigValue);
}

return false;

}

private boolean isChangeKey(ConfigChangeEvent changeEvent,String conditionalOnPropertyKey){
Set changeKeys = changeEvent.changedKeys();
if(!CollectionUtils.isEmpty(changeKeys) && changeKeys.contains(conditionalOnPropertyKey)){
return true;
}
return false;
}

private String getChangeKey(ConfigChangeEvent changeEvent, String[] conditionalOnPropertyKeys){
if(ArrayUtils.isEmpty(conditionalOnPropertyKeys)){
return null;
}
String changeKey = null;
for (String conditionalOnPropertyKey : conditionalOnPropertyKeys) {
if(isChangeKey(changeEvent,conditionalOnPropertyKey)){
changeKey = conditionalOnPropertyKey;
break;
}
}

return changeKey;
}

private BeanDefinitionRegistry getBeanDefinitionRegistry(){
ConfigurableApplicationContext configurableContext = (ConfigurableApplicationContext) applicationContext;
BeanDefinitionRegistry beanDefinitionRegistry = (DefaultListableBeanFactory) configurableContext.getBeanFactory();
return beanDefinitionRegistry;
}

private List listBasePackages(){
ConfigurableApplicationContext configurableContext = (ConfigurableApplicationContext) applicationContext;
return AutoConfigurationPackages.get(configurableContext.getBeanFactory());
}

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}

public void printAllBeans() {
String[] beans = applicationContext.getBeanDefinitionNames();
Arrays.sort(beans);
for (String beanName : beans) {
Class<?> beanType = applicationContext.getType(beanName);
System.out.println(beanType);
}
}

}

如果条件注解的值也是配置在apollo上，可能会出现依赖条件注解的bean的其他bean，在项目拉取apollo配置时，就已经注入spring容器中，此时就算条件注解满足条件，则引用该条件注解bean的其他bean，也会拿不到条件注解bean。此时有2种方法解决，一种是在依赖条件注解bean的其他bean注入之前，先手动注册条件注解bean到spring容器中，其核心代码如下

@Component
@Slf4j
public class RefreshBeanFactory implements BeanFactoryPostProcessor {

@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
Config config = ConfigService.getConfig(“order.properties”);
List basePackages = AutoConfigurationPackages.get(configurableListableBeanFactory);
for (String basePackage : basePackages) {
Set conditionalClasses = ClassScannerUtils.scan(basePackage, ConditionalOnProperty.class);
if(!CollectionUtils.isEmpty(conditionalClasses)){
for (Class conditionalClass : conditionalClasses) {
ConditionalOnProperty conditionalOnProperty = (ConditionalOnProperty) conditionalClass.getAnnotation(ConditionalOnProperty.class);
String[] conditionalOnPropertyKeys = conditionalOnProperty.name();
String beanConditionKey = this.getConditionalOnPropertyKey(config,conditionalOnPropertyKeys);
String conditionalOnPropertyValue = conditionalOnProperty.havingValue();
this.registerBeanIfMatchCondition((DefaultListableBeanFactory)configurableListableBeanFactory,config,conditionalClass,beanConditionKey,conditionalOnPropertyValue);
}
}
}

}

private void registerBeanIfMatchCondition(DefaultListableBeanFactory beanFactory,Config config,Class conditionalClass, String beanConditionKey, String conditionalOnPropertyValue) {
boolean isNeedRegisterBean = this.isNeedRegisterBean(config,beanConditionKey,conditionalOnPropertyValue);
String beanName = StringUtils.uncapitalize(conditionalClass.getSimpleName());
if(isNeedRegisterBean){
this.registerBean(config,beanFactory,beanName,conditionalClass);

}

}

public void registerBean(Config config,DefaultListableBeanFactory beanFactory, String beanName, Class beanClass) {
log.info(“registerBean->beanName:{},beanClass:{}”,beanName,beanClass);
BeanDefinitionBuilder beanDefinitionBurinilder = BeanDefinitionBuilder.genericBeanDefinition(beanClass);
BeanDefinition beanDefinition = beanDefinitionBurinilder.getBeanDefinition();
setBeanField(config,beanClass, beanDefinition);
beanFactory.registerBeanDefinition(beanName,beanDefinition);

}

private void setBeanField(Config config,Class beanClass, BeanDefinition beanDefinition) {
ConfigurationProperties configurationProperties = (ConfigurationProperties) beanClass.getAnnotation(ConfigurationProperties.class);
if(ObjectUtils.isNotEmpty(configurationProperties)){
String prefix = configurationProperties.prefix();
for (String propertyName : config.getPropertyNames()) {
String fieldPrefix = prefix + “.”;
if(propertyName.startsWith(fieldPrefix)){
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